How I manage: Thrombocytopaenia by Dr Li Tan

HOW I MANAGE THROMBOCYTOPENIA

Dr Li Huey Tan

Intensivist, Alfred Hospital

Clinical Lead Echocardiography, Epworth Hospital

Conflict of Interest - None

Dr Li Huey Tan

Intensivist, Alfred Hospital

Clinical Lead Echocardiography, Epworth Hospital

67 year old, Day 2 post CAG x 3 for TVDSinus rhythm, BP stable. ICC output15-20ml every 4 hours, due for ward discharge.Morning bloods showed Hb 9 g/dL, platelets 80 (150x109)

What would you do?

A. Transfuse 1 pool platelets as the patient still has drain output.

B. Repeat the FBC but probably just observe.

C. Withold the aspirin and Clexane.

D.Do a HITS screen. Duh..

E. Call Dr Yong…or haematology

Call Haematology?

Thrombocytopenia in ICU

• ~ 35-40% in intensive care patients. <150x 109/L. 5-20% Severe.• Bleeding risks (interventions- vascular catheters)• Delay in interventions, alteration in anticoagulation therapy

(aspirin, DVT prophylaxis), transfusions, concerns with heparin induced thrombocytopenia

What to do and when to do something?

EXPECTED

UNEXPECTED

ONSET (?count) & EVOLUTION

Common Causes (Hx, PE, Drugs)

DIAGNOSTIC(what to test)

THERAPEUTIC(what to do)

ONSET (?count) & EVOLUTION

Immunosuppresion Therapeutic Plasma Ex

Platelet Transfusion

FBC Blood film

Immunologic

Blood products Transfusion

Mechanisms of thrombocytopenia in ICU

patient. Greinacher, Selleng, ASH 2010

Mechanisms of thrombocytopenia in ICU

patient. Greinacher, Selleng, ASH 2010

Prognostic Marker

1. Marker for severity of illness

2. Higher MODS, APACHE score

3. Prolonged ICU stay

4. Increased mortality

What about the absolute count?

<20 x 109/L

• Marrow failure

• Severe coagulopathy (meningococcal sepsis, malaria)

• Immune mediated platelet consumption (ITP, TTP)

50-100 x109/L• Post-op (Bleeding or not

bleeding)• Bleeding• Medical, no bleeding

(sepsis, DIC <50x 109/L)• Chronic (bone marrow

dysplasia, liver disease, drugs, ITP, TTP, viral infection)

• Thromboembolic complications (APL Syndrome, HITs)

Uncommon cause (Need to know for ICU exam…)

Thrombotic Thrombocytopenic Purpura

• ADAMTS13 level low UL vWF

• life threatening thrombosis

• Rx-TPE (+ steroids)

MAHA

Fever TP

Renal failure

Neurologic

Uncommon cause (Need to know for ICU management)

Heparin Induced (Thrombotic) Thrombocytopenia Syndrome

When a patient is thrombocytopenic, would you order a HITS screen if you knew…

• It occurs in 0.3 – 0.5% ICU patients?

• Moderate TP was more likely a feature?

• Because it is an immune mediated response, the platelet count was only like to drop 4 to 5 days after heparin exposure?

• Very few do the 4Ts testing before deciding to order HITS screen?

• That just because HITS assay is + does not imply patient has HITS?

HIPA Postive

ELISA Postive 4 3

ELISA Equivocal 3 2

Positive10%

Equivocal7%

Negative83%

HITS Screen performed 2015 in ICU Melbourne Pathology

0

50

100

150

200

250

300

350

400

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41

Series1

Bite Size HITS

ELISA (Enzyme Immunoassay) anti PF4/heparin Abs

Serotonin Release Assay (Functional)

Cheap(er)FastHigh sensitivityDetects IgM

CostlySlowHigh specificityDetects IgG

Bite Size HITS

The relationship among the clinical expression of HIT (thrombocytopenia with or without thrombosis), the type of heparin used, and the antibodies that cause HIT. This can be

conceptualized as an “iceberg.”

John G. Kelton, and Theodore E. Warkentin Blood 2008;112:2607-2616

©2008 by American Society of Hematology

Risk factors for developing HITS

1. Exposure to heparin• Therapeutic>

prophylactic

• UFH > LMWH

2. Degree of PF4 release

• Surgical, trauma> Medical

Referencezzz

• Thrombocytopenia in the intensive care unit patient. Greinacher A, SellengK. Hematology Am Soc Hematol Educ Program. 2010

• How I evaluate and treat thrombocytopenia in the intensive care unit patient. Andreas Greinacher and Sixten Selleng. Blood 2016 128:3032-3042

• Tsai HM. Pathophysiology of thrombotic thrombocytopenic purpura. Int J Hematol. 2010 Jan

• Heparin-induced thrombocytopenia: a historical perspective. John G. Kelton, and Theodore E. Warkentin. Blood 2008;112:2607-2616

• Changes in platelet count after cardiac surgery can effectively predict the development of pathogenic heparin-dependent antibodies. BJH. Pouplardet al. 2005

• Early-onset and persisting thrombocytopenia in post-cardiac surgery patients is rarely due to heparin-induced thrombocytopenia, even when antibody tests are positive. J of Thrombosis and Haemostasis. Selleng et al. 2009

• Temporal Aspects of Heparin-Induced Thrombocytopenia. Theodore E. Warkentin, M.D., and John G. Kelton, M.D. N Engl J Med 2001

Thanks!